The Secretary of the Interior in August last invited my attention to the report of a Government director of the Union Pacific Railroad Company who had been specially instructed to examine the location, construction, and equipment of their road. I submitted for the opinion of the Attorney-General certain questions in regard to the authority of the Executive which arose upon this report and those which had from time to time been presented by the commissioners appointed to inspect each successive section of the work. After carefully considering the law of the case, he affirmed the right of the Executive to order, if necessary, a thorough revision of the entire road. Commissioners were thereupon appointed to examine this and other lines, and have recently submitted a statement of their investigations, of which the report of the Secretary of the Interior furnishes specific information. The report of the Secretary of War contains information of interest and importance respecting the several bureaus of the War Department and the operations of the Army. The strength of our military force on the 30th of September last was 48,000 men, and it is computed that by the 1st of January next this number will be decreased to 43,000. It is the opinion of the Secretary of War that within the next year a considerable diminution of the infantry force may be made without detriment to the interests of the country; and in view of the great expense attending the military peace establishment and the absolute necessity of retrenchment wherever it can be applied, it is hoped that Congress will sanction the reduction which his report recommends. While in 1860 sixteen thousand three hundred men cost the nation $16,472,000, the sum of $65,682,000 is estimated as necessary for the support of the Army during the fiscal year ending June 30, 1870. The estimates of the War Department for the last two fiscal years were, for 1867, $33,814,461, and for 1868 $25,205,669. The actual expenditures during the same periods were, respectively, $95,224,415 and $123,246,648. The estimate submitted in December last for the fiscal year ending June 30, 1869, was $77,124,707; the expenditures for the first quarter, ending the 30th of September last, were $27,219,117, and the Secretary of the Treasury gives $66,000,000 as the amount which will probably be required during the remaining three quarters, if there should be no reduction of the Army--making its aggregate cost for the year considerably in excess of ninety-three millions. The difference between the estimates and expenditures for the three fiscal years which have been named is thus shown to be $175,545,343 for this single branch of the public service.